Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add lennney/stop-that-shit/plugin install stop-that-shitWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/hooks/lennney/stop-that-shit/subagent-start)<a href="https://agentmods.dev/hooks/lennney/stop-that-shit/subagent-start"><img src="https://agentmods.dev/badge/hooks/lennney/stop-that-shit/subagent-start.svg" alt="Measured on agentmods" height="20"></a>Grade A, and why
SubagentStart scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the commands this hook runs, not an audit. A hook is shell that executes on your machine at the event it names, which is why every command in it is printed with what was found.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
64% identical to SessionStart — 9 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
What it actually says
{
"SubagentStart": [
{
"matcher": "*",
"hooks": [
{
"type": "command",
"command": "node \"${CLAUDE_PLUGIN_ROOT}/hooks/stop-that-shit-claude.cjs\"",
"timeout": 5
}
]
}
]
}What else hooks.json configures
This page is one entry in a file that holds 4. Installing the file brings all of them; each is measured and scanned on its own page.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 14 lines scan A 51428b8c9784
SubagentStart is a hook published in the GitHub repository lennney/stop-that-shit (1,439 stars, last pushed today), licensed MIT. Its token cost is not measured: a hook is shell that never enters the context. A static security scan graded it A with 0 findings. It is 64% identical to SessionStart, differing in 9 lines, and is treated as a copy.
Other hooks, from other repositories
Stop
Runs when the agent finishes a response, executing pause_detect.py via python3. From TerenceLiu98/prewalk.
SessionStart
Runs when a session starts, executing export_session_id.py via python3. From TerenceLiu98/prewalk.
SessionStart
Runs when a session starts on startup and resume, executing session-lifecycle-hook.mjs via node with --show-toplevel. From nikuscs/codex-multitask.
SessionStart
Runs when a session starts on startup, resume and clear, executing arckit-codex-hook.mjs. From tractorjuice/arckit-codex.
UserPromptSubmit
Runs when you submit a prompt, before the agent sees it, executing arckit-codex-hook.mjs. From tractorjuice/arckit-codex.
PreToolUse
Runs before the agent uses a tool for Read, Bash, apply_patch, Edit and Write tool calls, executing arckit-codex-hook.mjs. From tractorjuice/arckit-codex.